/*
 * Procedures for maintaining information about logical memory blocks.
 *
 * Peter Bergner, IBM Corp.	June 2001.
 * Copyright (C) 2001 Peter Bergner.
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */
#define pr_fmt(fmt) "memblock: " fmt

#include <errno.h>
#include <utils/cache.h>
#include <utils/utils.h>
#include <utils/pfn.h>
#include <seminix/init.h>
#include <seminix/string.h>
#include <seminix/param.h>
#include <seminix/memblock.h>
#include <seminix/dump_stack.h>
#include <seminix/mm.h>
#include <asm/sections.h>

static int memblock_can_resize __initdata_memblock;
static int memblock_debug __initdata_memblock;

#define memblock_dbg(fmt, ...) \
    if (memblock_debug) printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)

#define INIT_MEMBLOCK_REGIONS			128

#ifndef INIT_MEMBLOCK_RESERVED_REGIONS
#define INIT_MEMBLOCK_RESERVED_REGIONS		INIT_MEMBLOCK_REGIONS
#endif

static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock;
static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_RESERVED_REGIONS] __initdata_memblock;

struct memblock memblock __initdata_memblock = {
    .memory.regions		= memblock_memory_init_regions,
    .memory.cnt		= 1,	/* empty dummy entry */
    .memory.max		= INIT_MEMBLOCK_REGIONS,
    .memory.name		= "memory",

    .reserved.regions	= memblock_reserved_init_regions,
    .reserved.cnt		= 1,	/* empty dummy entry */
    .reserved.max		= INIT_MEMBLOCK_RESERVED_REGIONS,
    .reserved.name		= "reserved",

    .bottom_up		= false,
    .current_limit		= MEMBLOCK_ALLOC_ANYWHERE,
};

enum memblock_flags __init_memblock choose_memblock_flags(void)
{
    return MEMBLOCK_NONE;
}

/* adjust *@size so that (@base + *@size) doesn't overflow, return new size */
static inline phys_addr_t memblock_cap_size(phys_addr_t base, phys_addr_t *size)
{
    return *size = min(*size, PHYS_ADDR_MAX - base);
}

/*
 * Address comparison utilities
 */
static unsigned long __init_memblock memblock_addrs_overlap(phys_addr_t base1, phys_addr_t size1,
                       phys_addr_t base2, phys_addr_t size2)
{
    return ((base1 < (base2 + size2)) && (base2 < (base1 + size1)));
}

bool __init_memblock memblock_overlaps_region(struct memblock_type *type,
                    phys_addr_t base, phys_addr_t size)
{
    unsigned long i;

    for (i = 0; i < type->cnt; i++)
        if (memblock_addrs_overlap(base, size, type->regions[i].base,
                       type->regions[i].size))
            break;
    return i < type->cnt;
}

/**
 * __memblock_find_range_bottom_up - find free area utility in bottom-up
 * @start: start of candidate range
 * @end: end of candidate range, can be %MEMBLOCK_ALLOC_ANYWHERE or
 *       %MEMBLOCK_ALLOC_ACCESSIBLE
 * @size: size of free area to find
 * @align: alignment of free area to find
 * @flags: pick from blocks based on memory attributes
 *
 * Utility called from __memblock_find_in_range(), find free area bottom-up.
 *
 * Return:
 * Found address on success, 0 on failure.
 */
static phys_addr_t __init_memblock
__memblock_find_range_bottom_up(phys_addr_t start, phys_addr_t end,
                phys_addr_t size, phys_addr_t align,
                enum memblock_flags flags)
{
    phys_addr_t this_start, this_end, cand;
    u64 i;

    for_each_free_mem_range(i, flags, &this_start, &this_end) {
        this_start = clamp(this_start, start, end);
        this_end = clamp(this_end, start, end);

        cand = round_up(this_start, align);
        if (cand < this_end && this_end - cand >= size)
            return cand;
    }

    return 0;
}

/**
 * __memblock_find_range_top_down - find free area utility, in top-down
 * @start: start of candidate range
 * @end: end of candidate range, can be %MEMBLOCK_ALLOC_ANYWHERE or
 *       %MEMBLOCK_ALLOC_ACCESSIBLE
 * @size: size of free area to find
 * @align: alignment of free area to find
 * @flags: pick from blocks based on memory attributes
 *
 * Utility called from __memblock_find_in_range(), find free area top-down.
 *
 * Return:
 * Found address on success, 0 on failure.
 */
static phys_addr_t __init_memblock
__memblock_find_range_top_down(phys_addr_t start, phys_addr_t end,
                   phys_addr_t size, phys_addr_t align,
                   enum memblock_flags flags)
{
    phys_addr_t this_start, this_end, cand;
    u64 i;

    for_each_free_mem_range_reverse(i, flags, &this_start, &this_end) {
        this_start = clamp(this_start, start, end);
        this_end = clamp(this_end, start, end);

        if (this_end < size)
            continue;

        cand = round_down(this_end - size, align);
        if (cand >= this_start)
            return cand;
    }

    return 0;
}

/**
 * __memblock_find_in_range - find free area in given range
 * @size: size of free area to find
 * @align: alignment of free area to find
 * @start: start of candidate range
 * @end: end of candidate range, can be %MEMBLOCK_ALLOC_ANYWHERE or
 *       %MEMBLOCK_ALLOC_ACCESSIBLE
 * @flags: pick from blocks based on memory attributes
 *
 * Find @size free area aligned to @align in the specified range.
 *
 * When allocation direction is bottom-up, the @start should be greater
 * than the end of the kernel image. Otherwise, it will be trimmed. The
 * reason is that we want the bottom-up allocation just near the kernel
 * image so it is highly likely that the allocated memory.
 *
 * If bottom-up allocation failed, will try to allocate memory top-down.
 *
 * Return:
 * Found address on success, 0 on failure.
 */
phys_addr_t __init_memblock __memblock_find_in_range(phys_addr_t size,
                    phys_addr_t align, phys_addr_t start,
                    phys_addr_t end, enum memblock_flags flags)
{
    phys_addr_t kernel_end, ret;

    /* pump up @end */
    if (end == MEMBLOCK_ALLOC_ACCESSIBLE)
        end = memblock.current_limit;

    /* avoid allocating the first page */
    start = max_t(phys_addr_t, start, UTILS_PAGE_SIZE);
    end = max(start, end);
    kernel_end = __pa_symbol(_end);

    /*
     * try bottom-up allocation only when bottom-up mode
     * is set and @end is above the kernel image.
     */
    if (memblock_bottom_up() && end > kernel_end) {
        phys_addr_t bottom_up_start;

        /* make sure we will allocate above the kernel */
        bottom_up_start = max(start, kernel_end);

        /* ok, try bottom-up allocation first */
        ret = __memblock_find_range_bottom_up(bottom_up_start, end,
                              size, align, flags);
        if (ret)
            return ret;
    }

    return __memblock_find_range_top_down(start, end, size, align, flags);
}

/**
 * memblock_find_in_range - find free area in given range
 * @start: start of candidate range
 * @end: end of candidate range, can be %MEMBLOCK_ALLOC_ANYWHERE or
 *       %MEMBLOCK_ALLOC_ACCESSIBLE
 * @size: size of free area to find
 * @align: alignment of free area to find
 *
 * Find @size free area aligned to @align in the specified range.
 *
 * Return:
 * Found address on success, 0 on failure.
 */
phys_addr_t __init_memblock memblock_find_in_range(phys_addr_t start,
                    phys_addr_t end, phys_addr_t size,
                    phys_addr_t align)
{
    phys_addr_t ret;
    enum memblock_flags flags = choose_memblock_flags();

    ret = __memblock_find_in_range(size, align, start, end, flags);

    return ret;
}

static void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r)
{
    type->total_size -= type->regions[r].size;
    memmove(&type->regions[r], &type->regions[r + 1],
        (type->cnt - (r + 1)) * sizeof(type->regions[r]));
    type->cnt--;

    /* Special case for empty arrays */
    if (type->cnt == 0) {
        WARN_ON(type->total_size != 0);
        type->cnt = 1;
        type->regions[0].base = 0;
        type->regions[0].size = 0;
        type->regions[0].flags = 0;
    }
}

/**
 * memblock_double_array - double the size of the memblock regions array
 * @type: memblock type of the regions array being doubled
 * @new_area_start: starting address of memory range to avoid overlap with
 * @new_area_size: size of memory range to avoid overlap with
 *
 * Double the size of the @type regions array. If memblock is being used to
 * allocate memory for a new reserved regions array and there is a previously
 * allocated memory range [@new_area_start, @new_area_start + @new_area_size]
 * waiting to be reserved, ensure the memory used by the new array does
 * not overlap.
 *
 * Return:
 * 0 on success, -1 on failure.
 */
static int __init_memblock memblock_double_array(struct memblock_type *type,
                        phys_addr_t new_area_start,
                        phys_addr_t new_area_size)
{
    struct memblock_region *new_array, *old_array;
    phys_addr_t old_alloc_size, new_alloc_size;
    phys_addr_t old_size, new_size, addr, new_end;

    /* We don't allow resizing until we know about the reserved regions
     * of memory that aren't suitable for allocation
     */
    if (!memblock_can_resize)
        return -1;

    /* Calculate new doubled size */
    old_size = type->max * sizeof(struct memblock_region);
    new_size = old_size << 1;
    /*
     * We need to allocated new one align to UTILS_PAGE_SIZE,
     *   so we can free them completely later.
     */
    old_alloc_size = PAGE_ALIGN(old_size);
    new_alloc_size = PAGE_ALIGN(new_size);

    /* only exclude range when trying to double reserved.regions */
    if (type != &memblock.reserved)
        new_area_start = new_area_size = 0;

    addr = memblock_find_in_range(new_area_start + new_area_size,
                    memblock.current_limit,
                    new_alloc_size, UTILS_PAGE_SIZE);
    if (!addr && new_area_size)
        addr = memblock_find_in_range(0,
            min(new_area_start, memblock.current_limit),
            new_alloc_size, UTILS_PAGE_SIZE);

    new_array = addr ? __va(addr) : NULL;
    if (!addr) {
        pr_err("memblock: Failed to double %s array from %ld to %ld entries !\n",
               type->name, type->max, type->max * 2);
        return -1;
    }

    new_end = addr + new_size - 1;
    memblock_dbg("memblock: %s is doubled to %ld at [%pa-%pa]",
            type->name, type->max * 2, &addr, &new_end);

    /*
     * Found space, we now need to move the array over before we add the
     * reserved region since it may be our reserved array itself that is
     * full.
     */
    memcpy(new_array, type->regions, old_size);
    memset(new_array + type->max, 0, old_size);
    old_array = type->regions;
    type->regions = new_array;
    type->max <<= 1;

    if (old_array != memblock_memory_init_regions &&
         old_array != memblock_reserved_init_regions)
        memblock_free(__pa(old_array), old_alloc_size);

    BUG_ON(memblock_reserve(addr, new_alloc_size));

    return 0;
}

/**
 * memblock_merge_regions - merge neighboring compatible regions
 * @type: memblock type to scan
 *
 * Scan @type and merge neighboring compatible regions.
 */
static void __init_memblock memblock_merge_regions(struct memblock_type *type)
{
    unsigned long i = 0;

    /* cnt never goes below 1 */
    while (i < type->cnt - 1) {
        struct memblock_region *this = &type->regions[i];
        struct memblock_region *next = &type->regions[i + 1];

        if (this->base + this->size != next->base ||
            this->flags != next->flags) {
            BUG_ON(this->base + this->size > next->base);
            i++;
            continue;
        }

        this->size += next->size;
        /* move forward from next + 1, index of which is i + 2 */
        memmove(next, next + 1, (type->cnt - (i + 2)) * sizeof(*next));
        type->cnt--;
    }
}

/**
 * memblock_insert_region - insert new memblock region
 * @type:	memblock type to insert into
 * @idx:	index for the insertion point
 * @base:	base address of the new region
 * @size:	size of the new region
 * @flags:	flags of the new region
 *
 * Insert new memblock region [@base, @base + @size) into @type at @idx.
 * @type must already have extra room to accommodate the new region.
 */
static void __init_memblock memblock_insert_region(struct memblock_type *type,
                           int idx, phys_addr_t base,
                           phys_addr_t size,
                           enum memblock_flags flags)
{
    struct memblock_region *rgn = &type->regions[idx];

    BUG_ON(type->cnt >= type->max);
    memmove(rgn + 1, rgn, (type->cnt - idx) * sizeof(*rgn));
    rgn->base = base;
    rgn->size = size;
    rgn->flags = flags;
    type->cnt++;
    type->total_size += size;
}

/**
 * memblock_add_range - add new memblock region
 * @type: memblock type to add new region into
 * @base: base address of the new region
 * @size: size of the new region
 * @flags: flags of the new region
 *
 * Add new memblock region [@base, @base + @size) into @type.  The new region
 * is allowed to overlap with existing ones - overlaps don't affect already
 * existing regions.  @type is guaranteed to be minimal (all neighbouring
 * compatible regions are merged) after the addition.
 *
 * Return:
 * 0 on success, -errno on failure.
 */
int __init_memblock memblock_add_range(struct memblock_type *type,
                phys_addr_t base, phys_addr_t size,
                enum memblock_flags flags)
{
    bool insert = false;
    phys_addr_t obase = base;
    phys_addr_t end = base + memblock_cap_size(base, &size);
    unsigned int idx, nr_new;
    struct memblock_region *rgn;

    if (!size)
        return 0;

    /* special case for empty array */
    if (type->regions[0].size == 0) {
        WARN_ON(type->cnt != 1 || type->total_size);
        type->regions[0].base = base;
        type->regions[0].size = size;
        type->regions[0].flags = flags;
        type->total_size = size;
        return 0;
    }
repeat:
    /*
     * The following is executed twice.  Once with %false @insert and
     * then with %true.  The first counts the number of regions needed
     * to accommodate the new area.  The second actually inserts them.
     */
    base = obase;
    nr_new = 0;

    for_each_memblock_type(idx, type, rgn) {
        phys_addr_t rbase = rgn->base;
        phys_addr_t rend = rbase + rgn->size;

        if (rbase >= end)
            break;
        if (rend <= base)
            continue;
        /*
         * @rgn overlaps.  If it separates the lower part of new
         * area, insert that portion.
         */
        if (rbase > base) {
            WARN_ON(flags != rgn->flags);
            nr_new++;
            if (insert)
                memblock_insert_region(type, idx++, base,
                               rbase - base, flags);
        }
        /* area below @rend is dealt with, forget about it */
        base = min(rend, end);
    }

    /* insert the remaining portion */
    if (base < end) {
        nr_new++;
        if (insert)
            memblock_insert_region(type, idx, base, end - base, flags);
    }

    if (!nr_new)
        return 0;

    /*
     * If this was the first round, resize array and repeat for actual
     * insertions; otherwise, merge and return.
     */
    if (!insert) {
        while (type->cnt + nr_new > type->max)
            if (memblock_double_array(type, obase, size) < 0)
                return -ENOMEM;
        insert = true;
        goto repeat;
    } else {
        memblock_merge_regions(type);
        return 0;
    }
}

/**
 * memblock_add - add new memblock region
 * @base: base address of the new region
 * @size: size of the new region
 *
 * Add new memblock region [@base, @base + @size) to the "memory"
 * type. See memblock_add_range() description for mode details
 *
 * Return:
 * 0 on success, -errno on failure.
 */
int __init_memblock memblock_add(phys_addr_t base, phys_addr_t size)
{
    phys_addr_t end = base + size - 1;

    memblock_dbg("memblock_add: [%pa-%pa] %pF\n",
             &base, &end, (void *)_RET_IP_);

    return memblock_add_range(&memblock.memory, base, size, 0);
}

/**
 * memblock_isolate_range - isolate given range into disjoint memblocks
 * @type: memblock type to isolate range for
 * @base: base of range to isolate
 * @size: size of range to isolate
 * @start_rgn: out parameter for the start of isolated region
 * @end_rgn: out parameter for the end of isolated region
 *
 * Walk @type and ensure that regions don't cross the boundaries defined by
 * [@base, @base + @size).  Crossing regions are split at the boundaries,
 * which may create at most two more regions.  The index of the first
 * region inside the range is returned in *@start_rgn and end in *@end_rgn.
 *
 * Return:
 * 0 on success, -errno on failure.
 */
static int __init_memblock memblock_isolate_range(struct memblock_type *type,
                    phys_addr_t base, phys_addr_t size,
                    int *start_rgn, int *end_rgn)
{
    phys_addr_t end = base + memblock_cap_size(base, &size);
    unsigned int idx;
    struct memblock_region *rgn;

    *start_rgn = *end_rgn = 0;

    if (!size)
        return 0;

    /* we'll create at most two more regions */
    while (type->cnt + 2 > type->max)
        if (memblock_double_array(type, base, size) < 0)
            return -ENOMEM;

    for_each_memblock_type(idx, type, rgn) {
        phys_addr_t rbase = rgn->base;
        phys_addr_t rend = rbase + rgn->size;

        if (rbase >= end)
            break;
        if (rend <= base)
            continue;

        if (rbase < base) {
            /*
             * @rgn intersects from below.  Split and continue
             * to process the next region - the new top half.
             */
            rgn->base = base;
            rgn->size -= base - rbase;
            type->total_size -= base - rbase;
            memblock_insert_region(type, idx, rbase, base - rbase, rgn->flags);
        } else if (rend > end) {
            /*
             * @rgn intersects from above.  Split and redo the
             * current region - the new bottom half.
             */
            rgn->base = end;
            rgn->size -= end - rbase;
            type->total_size -= end - rbase;
            memblock_insert_region(type, idx--, rbase, end - rbase, rgn->flags);
        } else {
            /* @rgn is fully contained, record it */
            if (!*end_rgn)
                *start_rgn = idx;
            *end_rgn = idx + 1;
        }
    }

    return 0;
}

static int __init_memblock memblock_remove_range(struct memblock_type *type,
                      phys_addr_t base, phys_addr_t size)
{
    int start_rgn, end_rgn;
    int i, ret;

    ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
    if (ret)
        return ret;

    for (i = end_rgn - 1; i >= start_rgn; i--)
        memblock_remove_region(type, i);
    return 0;
}

int __init_memblock memblock_remove(phys_addr_t base, phys_addr_t size)
{
    phys_addr_t end = base + size - 1;

    memblock_dbg("memblock_remove: [%pa-%pa] %pS\n",
             &base, &end, (void *)_RET_IP_);

    return memblock_remove_range(&memblock.memory, base, size);
}

/**
 * memblock_free - free boot memory block
 * @base: phys starting address of the  boot memory block
 * @size: size of the boot memory block in bytes
 *
 * Free boot memory block previously allocated by memblock_alloc_xx() API.
 * The freeing memory will not be released to the buddy allocator.
 */
int __init_memblock memblock_free(phys_addr_t base, phys_addr_t size)
{
    phys_addr_t end = base + size - 1;

    memblock_dbg("   memblock_free: [%pa-%pa] %pF\n",
             &base, &end, (void *)_RET_IP_);

    return memblock_remove_range(&memblock.reserved, base, size);
}

int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
{
    phys_addr_t end = base + size - 1;

    memblock_dbg("memblock_reserve: [%pa-%pa] %pF\n",
             &base, &end, (void *)_RET_IP_);

    return memblock_add_range(&memblock.reserved, base, size, 0);
}

/**
 * memblock_setclr_flag - set or clear flag for a memory region
 * @base: base address of the region
 * @size: size of the region
 * @set: set or clear the flag
 * @flag: the flag to udpate
 *
 * This function isolates region [@base, @base + @size), and sets/clears flag
 *
 * Return: 0 on success, -errno on failure.
 */
static int __init_memblock memblock_setclr_flag(phys_addr_t base,
                phys_addr_t size, int set, int flag)
{
    struct memblock_type *type = &memblock.memory;
    int i, ret, start_rgn, end_rgn;

    ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
    if (ret)
        return ret;

    for (i = start_rgn; i < end_rgn; i++)
        if (set)
            memblock_set_region_flags(&type->regions[i], flag);
        else
            memblock_clear_region_flags(&type->regions[i], flag);

    memblock_merge_regions(type);
    return 0;
}

/**
 * memblock_mark_nomap - Mark a memory region with flag MEMBLOCK_NOMAP.
 * @base: the base phys addr of the region
 * @size: the size of the region
 *
 * Return: 0 on success, -errno on failure.
 */
int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size)
{
    return memblock_setclr_flag(base, size, 1, MEMBLOCK_NOMAP);
}

/**
 * memblock_clear_nomap - Clear flag MEMBLOCK_NOMAP for a specified region.
 * @base: the base phys addr of the region
 * @size: the size of the region
 *
 * Return: 0 on success, -errno on failure.
 */
int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size)
{
    return memblock_setclr_flag(base, size, 0, MEMBLOCK_NOMAP);
}

int __init_memblock memblock_mark_dma(phys_addr_t base, phys_addr_t size)
{
    return memblock_setclr_flag(base, size, 1, MEMBLOCK_DMA);
}

int __init_memblock memblock_clear_dma(phys_addr_t base, phys_addr_t size)
{
    return memblock_setclr_flag(base, size, 0, MEMBLOCK_DMA);
}

/**
 * __next_reserved_mem_region - next function for for_each_reserved_region()
 * @idx: pointer to u64 loop variable
 * @out_start: ptr to phys_addr_t for start address of the region, can be %NULL
 * @out_end: ptr to phys_addr_t for end address of the region, can be %NULL
 *
 * Iterate over all reserved memory regions.
 */
void __init_memblock __next_reserved_mem_region(u64 *idx,
                       phys_addr_t *out_start,
                       phys_addr_t *out_end)
{
    struct memblock_type *type = &memblock.reserved;

    if (*idx < type->cnt) {
        struct memblock_region *r = &type->regions[*idx];
        phys_addr_t base = r->base;
        phys_addr_t size = r->size;

        if (out_start)
            *out_start = base;
        if (out_end)
            *out_end = base + size - 1;

        *idx += 1;
        return;
    }

    /* signal end of iteration */
    *idx = ULLONG_MAX;
}

/**
 * __next__mem_range - next function for for_each_free_mem_range() etc.
 * @idx: pointer to u64 loop variable
 * @flags: pick from blocks based on memory attributes
 * @type_a: pointer to memblock_type from where the range is taken
 * @type_b: pointer to memblock_type which excludes memory from being taken
 * @out_start: ptr to phys_addr_t for start address of the range, can be %NULL
 * @out_end: ptr to phys_addr_t for end address of the range, can be %NULL
 *
 * Find the first area from *@idx, fill the out
 * parameters, and update *@idx for the next iteration.  The lower 32bit of
 * *@idx contains index into type_a and the upper 32bit indexes the
 * areas before each region in type_b.	For example, if type_b regions
 * look like the following,
 *
 *	0:[0-16), 1:[32-48), 2:[128-130)
 *
 * The upper 32bit indexes the following regions.
 *
 *	0:[0-0), 1:[16-32), 2:[48-128), 3:[130-MAX)
 *
 * As both region arrays are sorted, the function advances the two indices
 * in lockstep and returns each intersection.
 */
void __init_memblock __next_mem_range(u64 *idx,
                      enum memblock_flags flags,
                      struct memblock_type *type_a,
                      struct memblock_type *type_b,
                      phys_addr_t *out_start,
                      phys_addr_t *out_end)
{
    unsigned int idx_a = *idx & 0xffffffff;
    unsigned int idx_b = *idx >> 32;

    for (; idx_a < type_a->cnt; idx_a++) {
        struct memblock_region *m = &type_a->regions[idx_a];

        phys_addr_t m_start = m->base;
        phys_addr_t m_end = m->base + m->size;

        if (flags != m->flags)
            continue;

        if (!type_b) {
            if (out_start)
                *out_start = m_start;
            if (out_end)
                *out_end = m_end;
            idx_a++;
            *idx = (u32)idx_a | (u64)idx_b << 32;
            return;
        }

        /* scan areas before each reservation */
        for (; idx_b < type_b->cnt + 1; idx_b++) {
            struct memblock_region *r;
            phys_addr_t r_start;
            phys_addr_t r_end;

            r = &type_b->regions[idx_b];
            r_start = idx_b ? r[-1].base + r[-1].size : 0;
            r_end = idx_b < type_b->cnt ?
                r->base : PHYS_ADDR_MAX;

            /*
             * if idx_b advanced past idx_a,
             * break out to advance idx_a
             */
            if (r_start >= m_end)
                break;
            /* if the two regions intersect, we're done */
            if (m_start < r_end) {
                if (out_start)
                    *out_start =
                        max(m_start, r_start);
                if (out_end)
                    *out_end = min(m_end, r_end);
                /*
                 * The region which ends first is
                 * advanced for the next iteration.
                 */
                if (m_end <= r_end)
                    idx_a++;
                else
                    idx_b++;
                *idx = (u32)idx_a | (u64)idx_b << 32;
                return;
            }
        }
    }

    /* signal end of iteration */
    *idx = ULLONG_MAX;
}

/**
 * __next_mem_range_rev - generic next function for for_each_*_range_rev()
 *
 * @idx: pointer to u64 loop variable
 * @flags: pick from blocks based on memory attributes
 * @type_a: pointer to memblock_type from where the range is taken
 * @type_b: pointer to memblock_type which excludes memory from being taken
 * @out_start: ptr to phys_addr_t for start address of the range, can be %NULL
 * @out_end: ptr to phys_addr_t for end address of the range, can be %NULL
 *
 * Finds the next range from type_a which is not marked as unsuitable
 * in type_b.
 *
 * Reverse of __next_mem_range().
 */
void __init_memblock __next_mem_range_rev(u64 *idx,
                      enum memblock_flags flags,
                      struct memblock_type *type_a,
                      struct memblock_type *type_b,
                      phys_addr_t *out_start,
                      phys_addr_t *out_end)
{
    int idx_a = *idx & 0xffffffff;
    int idx_b = *idx >> 32;

    if (*idx == (u64)ULLONG_MAX) {
        idx_a = type_a->cnt - 1;
        if (type_b != NULL)
            idx_b = type_b->cnt;
        else
            idx_b = 0;
    }

    for (; idx_a >= 0; idx_a--) {
        struct memblock_region *m = &type_a->regions[idx_a];

        phys_addr_t m_start = m->base;
        phys_addr_t m_end = m->base + m->size;

        if (flags != m->flags)
            continue;

        if (!type_b) {
            if (out_start)
                *out_start = m_start;
            if (out_end)
                *out_end = m_end;
            idx_a--;
            *idx = (u32)idx_a | (u64)idx_b << 32;
            return;
        }

        /* scan areas before each reservation */
        for (; idx_b >= 0; idx_b--) {
            struct memblock_region *r;
            phys_addr_t r_start;
            phys_addr_t r_end;

            r = &type_b->regions[idx_b];
            r_start = idx_b ? r[-1].base + r[-1].size : 0;
            r_end = idx_b < (int)type_b->cnt ?
                r->base : PHYS_ADDR_MAX;
            /*
             * if idx_b advanced past idx_a,
             * break out to advance idx_a
             */

            if (r_end <= m_start)
                break;
            /* if the two regions intersect, we're done */
            if (m_end > r_start) {
                if (out_start)
                    *out_start = max(m_start, r_start);
                if (out_end)
                    *out_end = min(m_end, r_end);
                if (m_start >= r_start)
                    idx_a--;
                else
                    idx_b--;
                *idx = (u32)idx_a | (u64)idx_b << 32;
                return;
            }
        }
    }
    /* signal end of iteration */
    *idx = ULLONG_MAX;
}

/*
 * Common iterator interface used to define for_each_mem_pfn_range().
 */
void __init_memblock __next_mem_pfn_range(int *idx,
                unsigned long *out_start_pfn,
                unsigned long *out_end_pfn)
{
    struct memblock_type *type = &memblock.memory;
    struct memblock_region *r;

    while (++*idx < (int)type->cnt) {
        r = &type->regions[*idx];

        if (PFN_UP(r->base) >= PFN_DOWN(r->base + r->size))
            continue;
        break;
    }
    if (*idx >= (int)type->cnt) {
        *idx = -1;
        return;
    }

    if (out_start_pfn)
        *out_start_pfn = PFN_UP(r->base);
    if (out_end_pfn)
        *out_end_pfn = PFN_DOWN(r->base + r->size);
}

static phys_addr_t __init __memblock_alloc_range(phys_addr_t size,
                    phys_addr_t align, phys_addr_t start,
                    phys_addr_t end, enum memblock_flags flags)
{
    phys_addr_t found;

    if (!align) {
        /* Can't use WARNs this early in boot on powerpc */
        dump_stack();
        align = SMP_CACHE_BYTES;
    }

    found = __memblock_find_in_range(size, align, start, end, flags);
    if (found && !memblock_reserve(found, size)) {
        return found;
    }
    return 0;
}

phys_addr_t __init memblock_alloc_range(phys_addr_t size, phys_addr_t align,
                    phys_addr_t start, phys_addr_t end,
                    enum memblock_flags flags)
{
    return __memblock_alloc_range(size, align, start, end, flags);
}

phys_addr_t __init __memblock_alloc_base(phys_addr_t size,
                    phys_addr_t align, phys_addr_t max_addr,
                    enum memblock_flags flags)
{
    return __memblock_alloc_range(size, align, 0, max_addr, flags);
}

phys_addr_t __init memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
{
    phys_addr_t alloc;

    alloc = __memblock_alloc_base(size, align, max_addr, MEMBLOCK_NONE);

    if (alloc == 0)
        panic("ERROR: Failed to allocate %pa bytes below %pa.\n",
              &size, &max_addr);

    return alloc;
}

phys_addr_t __init memblock_phys_alloc(phys_addr_t size, phys_addr_t align)
{
    return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
}

/**
 * memblock_alloc_internal - allocate boot memory block
 * @size: size of memory block to be allocated in bytes
 * @align: alignment of the region and block's size
 * @min_addr: the lower bound of the memory region to allocate (phys address)
 * @max_addr: the upper bound of the memory region to allocate (phys address)
 *
 * The @min_addr limit is dropped if it can not be satisfied and the allocation
 * will fall back to memory below @min_addr. Also, allocation may fall back
 * to any node in the system if the specified node can not
 * hold the requested memory.
 *
 * The allocation is performed from memory region limited by
 * memblock.current_limit if @max_addr == %MEMBLOCK_ALLOC_ACCESSIBLE.
 *
 * The phys address of allocated boot memory block is converted to virtual and
 * allocated memory is reset to 0.
 *
 * In addition, function sets the min_count to 0 using kmemleak_alloc for
 * allocated boot memory block, so that it is never reported as leaks.
 *
 * Return:
 * Virtual address of allocated memory block on success, NULL on failure.
 */
static void * __init memblock_alloc_internal(
                phys_addr_t size, phys_addr_t align,
                phys_addr_t min_addr, phys_addr_t max_addr)
{
    phys_addr_t alloc;
    void *ptr;
    enum memblock_flags flags = choose_memblock_flags();

    if (!align) {
        dump_stack();
        align = SMP_CACHE_BYTES;
    }

    if (max_addr > memblock.current_limit)
        max_addr = memblock.current_limit;
again:
    alloc = __memblock_find_in_range(size, align, min_addr, max_addr, flags);
    if (alloc && !memblock_reserve(alloc, size))
        goto done;

    if (min_addr) {
        min_addr = 0;
        goto again;
    }

    return NULL;
done:
    ptr = phys_to_virt(alloc);

    return ptr;
}

/**
 * memblock_alloc_try_raw - allocate boot memory block without zeroing
 * memory and without panicking
 * @size: size of memory block to be allocated in bytes
 * @align: alignment of the region and block's size
 * @min_addr: the lower bound of the memory region from where the allocation
 *	  is preferred (phys address)
 * @max_addr: the upper bound of the memory region from where the allocation
 *	      is preferred (phys address), or %MEMBLOCK_ALLOC_ACCESSIBLE to
 *	      allocate only from memory limited by memblock.current_limit value
 *
 * Public function, provides additional debug information (including caller
 * info), if enabled. Does not zero allocated memory, does not panic if request
 * cannot be satisfied.
 *
 * Return:
 * Virtual address of allocated memory block on success, NULL on failure.
 */
void * __init memblock_alloc_try_raw(
            phys_addr_t size, phys_addr_t align,
            phys_addr_t min_addr, phys_addr_t max_addr)
{
    void *ptr;

    memblock_dbg("%s: %llu bytes align=0x%llx from=%pa max_addr=%pa %pF\n",
             __func__, (unsigned long long)size, (unsigned long long)align, &min_addr,
             &max_addr, (void *)_RET_IP_);

    ptr = memblock_alloc_internal(size, align,
                       min_addr, max_addr);

    return ptr;
}

/**
 * memblock_alloc_try_nopanic - allocate boot memory block
 * @size: size of memory block to be allocated in bytes
 * @align: alignment of the region and block's size
 * @min_addr: the lower bound of the memory region from where the allocation
 *	  is preferred (phys address)
 * @max_addr: the upper bound of the memory region from where the allocation
 *	      is preferred (phys address), or %MEMBLOCK_ALLOC_ACCESSIBLE to
 *	      allocate only from memory limited by memblock.current_limit value
 *
 * Public function, provides additional debug information (including caller
 * info), if enabled. This function zeroes the allocated memory.
 *
 * Return:
 * Virtual address of allocated memory block on success, NULL on failure.
 */
void * __init memblock_alloc_try_nopanic(
                phys_addr_t size, phys_addr_t align,
                phys_addr_t min_addr, phys_addr_t max_addr)
{
    void *ptr;

    memblock_dbg("%s: %llu bytes align=0x%llx from=%pa max_addr=%pa %pF\n",
             __func__, (unsigned long long)size, (unsigned long long)align, &min_addr,
             &max_addr, (void *)_RET_IP_);

    ptr = memblock_alloc_internal(size, align,
                       min_addr, max_addr);
    if (ptr)
        memset(ptr, 0, size);
    return ptr;
}

/**
 * memblock_alloc_try - allocate boot memory block with panicking
 * @size: size of memory block to be allocated in bytes
 * @align: alignment of the region and block's size
 * @min_addr: the lower bound of the memory region from where the allocation
 *	  is preferred (phys address)
 * @max_addr: the upper bound of the memory region from where the allocation
 *	      is preferred (phys address), or %MEMBLOCK_ALLOC_ACCESSIBLE to
 *	      allocate only from memory limited by memblock.current_limit value
 *
 * Public panicking version of memblock_alloc_try_nopanic()
 * which provides debug information (including caller info), if enabled,
 * and panics if the request can not be satisfied.
 *
 * Return:
 * Virtual address of allocated memory block on success, NULL on failure.
 */
void * __init memblock_alloc_try(
            phys_addr_t size, phys_addr_t align,
            phys_addr_t min_addr, phys_addr_t max_addr)
{
    void *ptr;

    memblock_dbg("%s: %llu bytes align=0x%llx from=%pa max_addr=%pa %pF\n",
             __func__, (unsigned long long)size, (unsigned long long)align, &min_addr,
             &max_addr, (void *)_RET_IP_);
    ptr = memblock_alloc_internal(size, align,
                       min_addr, max_addr);
    if (ptr) {
        memset(ptr, 0, size);
        return ptr;
    }

    panic("%s: Failed to allocate %llu bytes align=0x%llx from=%pa max_addr=%pa\n",
          __func__, (unsigned long long)size, (unsigned long long)align, &min_addr, &max_addr);
    return NULL;
}

/*
 * Remaining API functions
 */

phys_addr_t __init_memblock memblock_phys_mem_size(void)
{
    return memblock.memory.total_size;
}

phys_addr_t __init_memblock memblock_reserved_size(void)
{
    return memblock.reserved.total_size;
}

phys_addr_t __init memblock_mem_size(unsigned long limit_pfn)
{
    unsigned long pages = 0;
    struct memblock_region *r;
    unsigned long start_pfn, end_pfn;

    for_each_memblock(memory, r) {
        start_pfn = memblock_region_memory_base_pfn(r);
        end_pfn = memblock_region_memory_end_pfn(r);
        start_pfn = min_t(unsigned long, start_pfn, limit_pfn);
        end_pfn = min_t(unsigned long, end_pfn, limit_pfn);
        pages += end_pfn - start_pfn;
    }

    return PFN_PHYS(pages);
}

/* lowest address */
phys_addr_t __init_memblock memblock_start_of_DRAM(void)
{
    return memblock.memory.regions[0].base;
}

phys_addr_t __init_memblock memblock_end_of_DRAM(void)
{
    int idx = memblock.memory.cnt - 1;

    return (memblock.memory.regions[idx].base + memblock.memory.regions[idx].size);
}

static phys_addr_t __init_memblock __find_max_addr(phys_addr_t limit)
{
    phys_addr_t max_addr = PHYS_ADDR_MAX;
    struct memblock_region *r;

    /*
     * translate the memory @limit size into the max address within one of
     * the memory memblock regions, if the @limit exceeds the total size
     * of those regions, max_addr will keep original value PHYS_ADDR_MAX
     */
    for_each_memblock(memory, r) {
        if (limit <= r->size) {
            max_addr = r->base + limit;
            break;
        }
        limit -= r->size;
    }

    return max_addr;
}

void __init memblock_enforce_memory_limit(phys_addr_t limit)
{
    phys_addr_t max_addr = PHYS_ADDR_MAX;

    if (!limit)
        return;

    max_addr = __find_max_addr(limit);

    /* @limit exceeds the total size of the memory, do nothing */
    if (max_addr == PHYS_ADDR_MAX)
        return;

    /* truncate both memory and reserved regions */
    memblock_remove_range(&memblock.memory, max_addr,
                  PHYS_ADDR_MAX);
    memblock_remove_range(&memblock.reserved, max_addr,
                  PHYS_ADDR_MAX);
}

void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
{
    int start_rgn, end_rgn;
    int i, ret;

    if (!size)
        return;

    ret = memblock_isolate_range(&memblock.memory, base, size,
                        &start_rgn, &end_rgn);
    if (ret)
        return;

    /* remove all the MAP regions */
    for (i = memblock.memory.cnt - 1; i >= end_rgn; i--)
        if (!memblock_is_nomap(&memblock.memory.regions[i]))
            memblock_remove_region(&memblock.memory, i);

    for (i = start_rgn - 1; i >= 0; i--)
        if (!memblock_is_nomap(&memblock.memory.regions[i]))
            memblock_remove_region(&memblock.memory, i);

    /* truncate the reserved regions */
    memblock_remove_range(&memblock.reserved, 0, base);
    memblock_remove_range(&memblock.reserved,
            base + size, PHYS_ADDR_MAX);
}

void __init memblock_mem_limit_remove_map(phys_addr_t limit)
{
    phys_addr_t max_addr;

    if (!limit)
        return;

    max_addr = __find_max_addr(limit);

    /* @limit exceeds the total size of the memory, do nothing */
    if (max_addr == PHYS_ADDR_MAX)
        return;

    memblock_cap_memory_range(0, max_addr);
}

static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr)
{
    unsigned int left = 0, right = type->cnt;

    do {
        unsigned int mid = (right + left) / 2;

        if (addr < type->regions[mid].base)
            right = mid;
        else if (addr >= (type->regions[mid].base +
                  type->regions[mid].size))
            left = mid + 1;
        else
            return mid;
    } while (left < right);
    return -1;
}

bool __init_memblock memblock_is_reserved(phys_addr_t addr)
{
    return memblock_search(&memblock.reserved, addr) != -1;
}

bool __init_memblock memblock_is_memory(phys_addr_t addr)
{
    return memblock_search(&memblock.memory, addr) != -1;
}

bool __init_memblock memblock_is_map_memory(phys_addr_t addr)
{
    int i = memblock_search(&memblock.memory, addr);

    if (i == -1)
        return false;
    return !memblock_is_nomap(&memblock.memory.regions[i]);
}

/**
 * memblock_is_region_memory - check if a region is a subset of memory
 * @base: base of region to check
 * @size: size of region to check
 *
 * Check if the region [@base, @base + @size) is a subset of a memory block.
 *
 * Return:
 * 0 if false, non-zero if true
 */
bool __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size)
{
    int idx = memblock_search(&memblock.memory, base);
    phys_addr_t end = base + memblock_cap_size(base, &size);

    if (idx == -1)
        return false;
    return (memblock.memory.regions[idx].base +
         memblock.memory.regions[idx].size) >= end;
}

/**
 * memblock_is_region_reserved - check if a region intersects reserved memory
 * @base: base of region to check
 * @size: size of region to check
 *
 * Check if the region [@base, @base + @size) intersects a reserved
 * memory block.
 *
 * Return:
 * True if they intersect, false if not.
 */
bool __init_memblock memblock_is_region_reserved(phys_addr_t base, phys_addr_t size)
{
    memblock_cap_size(base, &size);
    return memblock_overlaps_region(&memblock.reserved, base, size);
}

void __init_memblock memblock_trim_memory(phys_addr_t align)
{
    phys_addr_t start, end, orig_start, orig_end;
    struct memblock_region *r;

    for_each_memblock(memory, r) {
        orig_start = r->base;
        orig_end = r->base + r->size;
        start = round_up(orig_start, align);
        end = round_down(orig_end, align);

        if (start == orig_start && end == orig_end)
            continue;

        if (start < end) {
            r->base = start;
            r->size = end - start;
        } else {
            memblock_remove_region(&memblock.memory,
                           r - memblock.memory.regions);
            r--;
        }
    }
}

void __init_memblock memblock_set_current_limit(phys_addr_t limit)
{
    memblock.current_limit = limit;
}

phys_addr_t __init_memblock memblock_get_current_limit(void)
{
    return memblock.current_limit;
}

static void __init_memblock memblock_dump(struct memblock_type *type)
{
    phys_addr_t base, end, size;
    enum memblock_flags flags;
    unsigned int idx;
    struct memblock_region *rgn;

    pr_info(" %s.cnt  = 0x%lx\n", type->name, type->cnt);

    for_each_memblock_type(idx, type, rgn) {
        base = rgn->base;
        size = rgn->size;
        end = base + size - 1;
        flags = rgn->flags;
        pr_info(" %s[%#x]\t[%pa-%pa], %pa bytes flags: %#x\n",
            type->name, idx, &base, &end, &size, flags);
    }
}

void __init_memblock __memblock_dump_all(void)
{
    pr_info("MEMBLOCK configuration:\n");
    pr_info(" memory size = %pa reserved size = %pa\n",
        &memblock.memory.total_size,
        &memblock.reserved.total_size);

    memblock_dump(&memblock.memory);
    memblock_dump(&memblock.reserved);
}

void __init_memblock memblock_dump_all(void)
{
    if (memblock_debug)
        __memblock_dump_all();
}

void __init memblock_allow_resize(void)
{
    memblock_can_resize = 1;
}

static int __init early_memblock(char *p)
{
    if (p && strstr(p, "debug"))
        memblock_debug = 1;
    return 0;
}
early_param("memblock", early_memblock);
